Explosive jar



1965 M. M. KlNLEY V 3,199,594

EXPLOSIVE JAR Filed Jan. 8, 1962 4 Sheets-Sheet l 52?" Mrs? Z i Z BY -i-I i #vM/M J2 z M. M. KINLEY Aug. 10, 1965 EXPLOS IVE JAR 4 Sheets-Sheet2 Filed Jan. 8, 1962 Myra/7 M /K//7/e5 INVENTOR.

HTTOR/VEVJ:

M. M. KINLEY Aug. 10, 1965 EXPLOSIVE JAR 4 Sheets-Sheet 3 Filed Jan. 8,1962 Myra/7 M /(//7 /e IN VEN TOR.

ATTO/P/VEKS.

Aug. 10, 1965 M. M. KlNLEY 3,199,594

EXPLOSIVE JAR Filed Jan. 8, 1962 4 Sheets-Sheet 4 Myra/2 M /f//7 /eyINVENTOR.

W4 4i M United States Patent 3,199,594 EXPLGSEVE EAR Myron M. Kinley,Chichasha, (thin, assign-or to .iohn C. Kinley, Houston, Tex. Filed inn.8, 1952, Ser. No. 166,734- 9 Qlaims. (Cl. res-es This application is acontinuation-in-part of application, Serial No. 44,925, filed July 25,1960, now abandoned.

This invention relates to new and useful improvements in devices forimparting a jarring or impact force, and particularly to an explosivejar or tool for imparting a jarring force in a well.

Mechanical jars and hydraulic jars have previously been the only typesof jars or jarring devices available for imparting longitudinal jarringstrokes in well operations. Although mechanical jars which may belowered on and operated by a wire line are used, they generally cannotdeliver a very substantial jarring blow; therefore, most jars heretoforeknown are lowered into an oil well or the like on well tubing or pipestring which involves the usual diiliculties associated with theconnecting and disconnecting of the sections of the string during therunning in and withdrawal of the jars from the well. In the deeperwells, such difliculties are, of course, increased. Furthermore, in someinstances, even the mechanical and hydraulic jars which are lowered onthe tubing string do not deliver an adequate enough jarring blow torelease a stuck fish, and then the time required for the connection anddisconnection during the lowering and raising of the jar in the well iscompletely lost.

An object of the present invention is to provide a new and improvedjarring device capable of delivering a longitudinal jarring blow andwhich is adapted to be lowered in a well or the like on a wire line orsimilar flexible support.

An important object of this invention is to provide a new and improvedjar which is actuated by the firing of an explosive to provide anincreased jarring or impact force as compared to prior known mechanicaland bydraulic jars.

An important object of this invention is to provide a new and improvedjar which is actuated by the firing of an explosive to provide anincreased jarring or impact force as compared to prior known mechanicaland hydraulic jars, which jar incorporates means for relieving thepressure in the jar to inhibit excessive build up of pressure therein.

A further object of this invention is to provide a new and improvedjarring device which is adapted to have diiferent jarring heads mountedtherewith for performing various operations with the device such asjarring a stuck fish loose in a well, taking a lead impression of theupper end of a stuck fish in a well, and puncturing a bull plug at thelower end of a pipe string.

A still further object of the present invention is to provide a jarwhich obtains a more accurate impression Patented Aug". 3%, 1965 "iceand partly in section, of the upper, intermediate, and lower portions,respectively, of the preferred form of the explosive jar of thisinvention;

H6. 2 is a cross-sectional view, taken on line 22 of FIG. 1A;

FIG. 3 is a cross-sectional View, taken on line 33 of PEG. 1C;

FIG. 4 is a vertical sectional view illustrating a modified form of thelower portion of the explosive jar or tool of this invention.

FIG. 5 is a vertical sectional view of another modified lower portion ofthe jar or tool of this invention, shown in position for puncturing abull plug;

FIG. 6 is a vertical sectional view of another modified lower portion ofthe explosive jar or tool of this invention; and

PEG. 7 is a vertical sectional view of still another modified lowerportion of the explosive jar or tool of this invention.

In the drawings, the letter B designates generally the hollow or tubularbody of this invention which is preferably formed of a metal such assteel and which is also preferably formed in several parts, including amain body portion it), a lower body portion ii, an upper body portion12, and an upper body adapter 14. As will be explained in detail, thebody B includes a hollow chamber or bore lilo for receiving an explosiveE such as an ordinary gun shell or bullet. Such explosive E is adaptedto be fired or detonated by a manipulation of the wire line W or otherflexible line upon which the tool is supported and lowered and withdrawnin an oil well or other similar type of location. The explosion from theexplosive E imparts a longitudinal movement to a force transmittingmember or hammer H which is supported within the body B. Such movementof the hammer H with respect to the body B is transmitted to an anvil Aor other jarring member for imparting a jarring force thereto which maybe transmitted in various ways as will be more fully explained. Thus,with the tool or jar of this invention, a jar is obtained by means of anexplosion within the body of the jar or tool and such explosion providesan extremely great force for producing a longitudinal jarring actionwhich is far greater than the longitudinal jarring forces heretoforeknown or obtained with conventional mechanical and hydraulic jars.Furthermore, the high force of this device for the jarring action isobtained even though the device is lowered on a wire line or otherflexible line, and therefore the tool can be rapidly lowered and raisedin a well while at the same time obtaining an extremely hard jarringforce with the tool or jar of this invention.

Considering the invention more in detail, the body portion 19 hasinternal threads Nib formed thereon which are in threaded engagementwith external threads 11b on the lower body portion 11 for therebyconnecting the main body portion it and the lower body portion 11together. Of course, it will be appreciated that other suitable meansfor connecting such body portions 10 and 13. together may be providedand in some instances they may be made integral. The bore 11a of thelower body portion 11 is in alignment with and forms a continuation ofthe bore ltia of the main body portion 1%. A shear disk 2 3' formed ofbrass or a similar relatively soft material capable of being sheared ispositioned betweenthe upper end of the lower body portion 11 and anannular lateral shoulder 1153c formed in the bore Min of the main bodyportion 10. Thus, when the threads 10b and 11b are interengaged and arethreaded up tightly, the end 110 tightly engages the shear disk 28 tohold same in contact with the shoulder ltic. Such shear disk or platesupports a longitudinally movable hammer or piston H which is positionedin the bore 10a of the body 19. A wadding of rubber or other material 21is positioned between the explosive E and the upper end of the hammer orpiston H for keeping the explosion gases from leaking past the hammer Hwhen the explosion or detonation of the explosive E occurs.

As previously mentioned, the explosive E may be in the form of anordinary gun shell or bullet and as shown in FIG. 1B, the explosive Eincludes a shell 23 which has powder 24 or other explosive materialtherein. A percussion detonator cap 25 is mounted in the upper end ofthe shell 23 for detonating or firing the powder when the cap 25 iscontacted by a firing pin 27. The shell 23 has an annular flange 2311 atits upper end and a closure head 232; at its lower end. The flange 23arests upon an annular laterally extending shoulder or surface 19d of themain body portion 16.

The shell 23 is retained in position on the flange 19d by the engagementof the lower end 14a of the body adapter 14 with the upper end of theshell 23;. Such contact is maintained due to the threaded connectionbetween the main body portion 16 and the body adapter M which isprovided by the interengaging threads 102 on the body portion 10 andexternal threads lab on the body adapter 14. Of course, any othersuitable connection means between the bcdy portion 10 and the bodyadapter 14 may be provided, and in some cases, they may even beintegral.

The adapter 14 is provided with a lower tapered lower bore 14c in whichthe firing pin 27 is positioned. Such pin 27 is also tapered so as tohave a larger diameter at its lower portion than at its upper portion.In that way, when the explosive or shell E is detonated, the firing pin27 will be prevented from being blown or discharged upwardly in the bore14c, and therefore the pressures or gases of the explosion will beconfined below the firing pin 27. The body adapter 14 also has an upperbore 14d which is cylindrical and which forms a continuation of the bore14c. A vent hole or holes 142 is provided from the bore 14d to theexterior of the tool to prevent the entrapment of fluid or gas below afiring pin extension or rod 3t) positioned in the bore 14d. Thus, aswill be more fully explained, the extension or rod 39 is longitudinallymovable within the adapter 14 for imparting an impact to the firing pin27. The vent or vents 14c permit the escape of any gas or fiuid belowsuch firing pin extension or rod 30 during the downward movementthereof, which as explained, prevents the entrapment of such fluid orgases and therefore prevents a fluid lock of the extension 30 in thebore 1%. Actually, the pin 27 and the extension 30 could be made of onepiece since they move together, but for ease of manufacture andassembly, they are made in the two pieces as illustrated. The upper endof the body adapter 14 is provided with an annular groove 14] and anannular downwardly extending surface 14g to provide a fishing neck forengagement by any conventional fishing tool when the upper body portion12 has been separated from the body adapter 14-, as will be more fullyexplained.

Under normal conditions of operation, the body portion 12 is connectedto the body adapter 14 by means of interconnecting shear pins 32 ofbrass or other similar shearable material. As best seen in FIG. 2, suchpins extend laterally through the body adapter 14 and project intoopenings 12a formed in the upper body portion 12. Such pins 32 aresheared or severed by an upward pull on the upper body portion 12 with asutficient force to move the body portion 12 relative to the bodyadapter 14. This would not normally occur during the lifting of thetool, but it could be accomplished intentionally by an upward jar aswill be explained. The body portion i2 has a bore 12b into which thebody adapter 14 extends to make the connection previously described withthe shear pins 32. Other types of shearable connections may, of course,be utilized to connect the body portion 12 and the body adapter 14together. A vent hole or holes 12c is provided in the wall of the bodyportion 12 for establishing fluid communication between the interior orbore 12b of the body portion 12 and the exterior thereof to prevententrapment of fluid or gas below a firing head 35 which is mounted withthe body portion 12 for longitudinal movement with respect thereto.

The firing head 35 is provided with a contact section 35a which has adiameter no greater than the diameter of the bore 14d so that it canenter the bore 14d for striking or hitting the upper end of the firingpin extension 30. During the running in of the tool in a well, thefiring head 35 is positioned as shown in FIG. 1A so that the contactsection 35a is above the upper end of the extension 30 and out ofcontact therewith. Such position of the firing head 35 is maintained bythe engagement of an annular shoulder 35b on the head 35' with acorresponding annular shoulder 12d formed in the bore of the bodyportion 12.

A metal shear pin 36 formed of brass or other similar material extendsthrough the firing head 35 and rests on a support washer 37 which inturn rests upon a lateral shoulder 122 formed on the body portion 12.Thus, under normal conditions, the firing head 35 is prevented frommoving longitudinally in either direction with respect to the bodyportion 12, but when the pin as is sheared or severed, then the firinghead 35 may move downwardly with respect to the body portion 12 forcontacting the firing ,in extension 30 which imparts movement to thefiring pin 27 for detonating or firing the explosive E.

The firing head 35 is connected to a connector sub 41) by any suitablemeans such as internal threads 40a which are in threaded engagement withexternal threads 35c at the upper end of the firing head 35. A lock pinor pins 41 extends through suitable openings in the firing head 35' andthe connector sub for preventing an inadvertent release of the threads35c and 43a during the use of the tool. The sub 4i) has a reduceddiameter area 461: and an annular flange 40c which is downwardlyinclined to provide a fishing neck for engagement by a conventionalfishing tool in the event the portion of the tool above the sub 44 isreleased during the use of the tool in a well.

The upper end of the connector sub 49 has external threads 4001 formedthereon which are in threaded engagement with internal threads 45aformed at the lower end of a weight 4-5. The weight 4-5 is provided inconnection with the tool in the event it is necessary to provideadditional weight to the body B to prevent or limit the upward travel ofthe body B in the well when the explosion of the explosive E occurs. Inother words, when the explosion of the explosive E occurs, there will bea tendency for the hammer H to move downwardly and the body B to moveupwardly. However, if the weight of the body B together with the weightof the weight member 45 are sufficient to prevent the body B from movingupwardly, all of the downward force, or substantially all of such force,will be transmitted to the hammer H for a downward movement thereof.

Such weight 45 may take numerous forms, but as illustrated, such weight45 is merely an elongate bar of solid steel or other metal which isthreaded to the connector sub 40 as explained. The upper end of theweight 45 is preferably connected to a conventional wire line mechanicaljar J in any known manner. Such jar J is of known construction andmerely operates to provide for a mechanical jar upon the manipulation ofthe wire line W connected at its upper end. The jar J is of the typewhich provides both an upward jar and a downward jar when desired.

The anvil A may take numerous forms and may serve numerous purposes. Oneform of the anvil A is shown in FIG. 1C and other possible forms of theanvil are illustrated in FIGS. 4, 5, and 6, as will be explained.

Considering the anvil A of FIG. 1C, such anvil or jarring member A is soconstructed that it is adapted to jar a stuck choke or other fish in awell. The anvil A is mounted for limited longitudinal movement withinthe enlarged bore 11d of the lower body portion 11. The anvil A has anupper annular surface 559 which is adapted to contact a lateral shoulderlle in the bore of the lower body portion 11 so that the upward movementof the anvil A is limited in the body portion 11. It should also benoted that the upper end of the anvil A is positioned a considerabledistance below the lower end of the hammer H. Such spacing provides forthe travel or stroke of the hammer H to develop the momentum and thejarring force prior to the contact of the hammer H with the anvil A. Avent hole or holes 11 are provided in the wall of the lower body portion11 to prevent the entrapment of fiuid or gases below the hammer H as ittravels downwardly within the body portion 11 during the jarring stroke.

The anvil A also has a lower annular shoulder 51 which is adapted tocontact the upper end of an annular split nut 52 which is threaded withits external threads 52a into internal threads llg of the lower bodyportion 11. The lower end 53 of the anvil A shown in FIG. 1C is recessedto facilitate engagement and contact with the stuck object or choke inthe well to be loosened by the jarring action with the jar of thisinvention, but various configurations and shapes may be provided forsuch lower end 53 as will be understood by those skilled in the art. inorder to retain the various threaded sections together, metal lock ringsmay be used such as are indicated at 55 and 56 with bent flanges orprojections in the known manner.

In the use or operation of the jar or tool of this invention with theanvil A at its lower end, the tool or jar is lowered in a well on thewire line W which may be a piano wire or other similar flexible line.During such running in of the tool or jar of this invention, the firinghead 35 is maintained in the position shown in FIGURE 1A and the hammerH is maintained in the position shown in FIGS. 13 and 1C. The shear pin36 maintains the firing head 35 in its inactive position while the sheardisk 2%? maintains the hammer H in its inactive position. The jar ortool of this invention is lowered until the lower end 53 of the anvil Ais in contact with the choke or other stuck object or fish to be jarredwith the tool or jar of this invention. Then, the wire line ismanipulated to operate the wire line mechanical jar I in the knownmanner for imparting a sulficient jarring force to the weight 45 and theconnector sub 46 to shear the pin 36. When the pin 36 is sheared orsevered, the firing head 35 moves downwardly, and the contact portion35a engages the upper end of the firing pin extension 39 to impart adownward force to such firing in extension 39. The downward force of thepin extension 33 is transmitted to the firing pin 27 and the impact fromthe pin 27 on the cap 25 causes a detonation or firing of the explosive24 within the shell 23. Such explosion creates a terrific pressure as iswell known and since such pressure is conihied within the bore 1%, theexplosion force is transmitted downwardly against the head of the hammerH. Such force acting on the hammer H is sufiicient to immediately shearthe disk 2% and to cause the hammer or piston H to move rapidlydownwardly through the bore 11a of the lo er body portion 11 and intocontact with the upper end of the anvil A. As previously pointed out,the weight of the body B and any weight such as the weight 45 thereaboveprevents the upward movement of the body B during such explosion. Thejarring force transmitted to the anvil or jarring member A is thusimparted to any object such as a stuck choke or fish below the anvil Aand engaged thereby. The amount of jarring force thus obtained issubstantially greater than is possible 6 with the known types ofmechanical and hydraulic jars used in wells.

In the event the jar fails to operate properly or becomes stuck, theshear pins 32 may be sheared by an upward jar with the wire linemechanical jar I so as to pull the upper body portion 12 upwardly awayfrom the body adapter 14, leaving the fishing neck 14g exposed forengagement by a conventional fishing tool. In some instances, thethreads 45a and 4M may be separated to expose the fishing neck 4G0 forengagement by a fishing tool rather than releasing the shear pins 32.

When it is desired to remove the tool or jar of this invention from thewell, assuming that it is not stuck in the well itself, the wire line Wis raised to thereby raise the entire tool or jar to the surface for theinsertion of a new shell or explosive E for another jar when desired.

in PEG. 4, a modification of the invention is shown wherein the lowerportion of the jar or tool of this invention is modified. The partsshown in FIG. 4 which are identical with those shown in FIG. 1C bear thesame numerals. The anvil A-ll shown in FIG. 4 is modified as compared tothe anvil A of FIG. 1C. The anvil A-l has an upper annular shoulder 154which limits the upward travel of the anvil Al by engagement with theshoulder lie. The anvil A-fl also has a lower annular shoulder 151 whichis adapted to engage the upper end of the split retaining nut 52. Thetravel or stroke of the anvil A4 is longer than that of the anvil Awhich is accomplished by spacing the shoulder 151 from the upper end ofthe split nut 52 a greater amount than the distance between the shoulder51 and the upper end of the split nut 52 in the FlG. 1C modification.

Additionally, the anvil or jarring member A-l has a modified lower endwith a cavity 153 and vent holes 53a communicating therewith and withcircumferentially spaced longitudinal grooves 151%. Such cavity 153 isadapted to receive an impression member fill (shown in dotted lines)which is formed therein by pouring molten lead into the cavity 153 andthe grooves 15317. The vents 153a are not filled with the lead. Suchimpression member may be formed of impression materials other than leadso long as the material thereof is relatively soft and is capable ofbein impressed or deformed by the upper end of a stuck fish or object ina wel In other words, during the use of the anvil or jarring member A-l,the impression member St is in contact with the upper end of the stuckfish or object in the well prior to the explosion within the jar or toolof this invention. When the explosion of the explosive E occurs, theimpression member fill is forced downwardly with the jarring actionaround the upper end of the stuck fish or object in the well to providea cavity in the member 8i) which conforms with the external shape of theupper end of the stuck fish or object. In that way, an impression ismade of the upper end of such stuck fish or object and when the tool orjar of this invention is retrieved to the surface of the well, theoperator at the surface will then know what type of fishing operation isnecessary and what type of fishing tool should be employed to recoverthe stuck fish or object.

The operation of the form of the invention shown in FIG. 4 is identicalwith the form previously described in connection with FEGS. lAlC, exceptfor the obtaining of the impression with the device of FIG. 4 instead ofthe obtaining of the jar as with the device of FIGS. lA-lC.

Another modified form of the invention is illustrated in FIG. 5 whereinthe lower portion of the modified tool is illustrated with the partswhich are the same as in FIGS. 1A-1C having the same numerals. The anvilA-Z in FIG. 5 corresponds with the anvil A-ll and the anvil A, exceptthat it is modified for providing a puncturing action when the explosionoccurs in the tool or jar. Thus, the anvil or jarring member A-2includes annular shoulders 25% and 251 which basically correspond with'2 the shoulders and 151 in FIG. 4. The lower end of the anvil orjarring member A-Z is formed with a point 253 so that when the anvil orjarring member A-2 is forced downwardly with the jarring impact aspreviously explained in connection with FIGS. lA-lC, a puncture can bemade in a member such as the bull plug P illustrated in FIG. 5. Suchbull plug P is of conventional construction and is merely illustrated byway of example.

During the course of well operations, it often becomes desirable to openthe bull plug P to conduct well operations therebelow. Heretofore, therehas been no satisfactory way of obtaining the initial puncture in thebull plug. With this device as shown in FIG. 5, the pointed end 253 isforced through the bull plug P with a sufficient jarring force toactually open the plug for subsequent widening if necessary. Additionalanvils may be used in subsequent jarring actions which have a greaterwidth to more fully enlarge the opening obtained by the initial puncturewith the pointed end 253 so that the bull plug P may be actually openedto substantially the same extent as the internal diameter of the casingto which the plug P is connected. Then, additional well operations maybe performed below the plug P by the lowering of well tools through theruptured bull plug P to the area therebelow.

In the modification of the invention shown in FIGS. 14, the tool isconstructed so that well fluids may pass into the body B through theholes 11f, as the body B is lowered into the well bore on the line W.

As noted herein with regard to FIG. 1C, holes or passage means 11 in thelower body portion 11 provide a means to relieve the fluid pressure fromthe body B so that substantially the full force of the explosive B maybe transmitted to the hammer H.

In FIGS. 6 and 7, another modification of the invention is illustratedin which the well fluids are sealed off from entering the lower portion11' of the body B. The parts shown in FIGS. 6 and 7 which are identicalwith those shown in FIGS. 1C and 4 bear the same numerals. The anvil A3shown in FIGS. 6 and 7 is modified as compared to the anvil A of FIG. 4.Also, the lower body portion 11 is modified as compared to the body 11of FIGS. 1C and 4.

The anvil A3 has an upper annular shoulder which limits the upwardtravel of the anvil A-S by engagement with the lower annular edge ofshoulder 16. The anvil A-3 also has a lower annular shoulder 351 whichis adapted to engage the upper end of the split retaining nut 52. Thetravel or stroke of anvil A-3 is longer than that of the anvil A whichis accomplished by spacing the shoulder 351 from the upper end of thesplit nut 52 a greater amount than the distance between the shoulder 51and the upper end of the split nut 52 in the FIG. 1C modification.

The anvil A-3 has a cavity 153 in the lower end thereof and vent holes153a. Circumferentially arranged projections 253a and grooves 2535 arepreferably provided in the cavity for more securely holding theimpression member 86' in place in the cavity 153, although the cavity153 may have a smooth bore if desired.

The impression member 3% is shown as being formed of lead wool 8th: andlead fidb covering the lead wool. The impression member 89 may be formedof impression materials other than lead so long as the material thereofis capable of being impressed or deformed by the upper end of a stuckfish or object in a well. The lead 80b is shown as assuming the form ofa lead disk 80:: which is placed over the lead wool dda and then moltenlead is poured over the disk 890 to form the lead layer 80b whichextends into the circumferential grooves 25311. The vents 1530 are open.

The anvil A-3 is used to obtain impressions in the same manner asdescribed with regard to the anvil A-l of FIG. 4. The arrangement andrelationship of lead wool 80a and lead 891; enable an accurate and deepimpression of the fish in the well bore to be obtained. This in turnindicates to the operator the type of fishing tool which .is best suitedto engage the fish and retrieve it from the well here.

The lower end of hammer H is shown in FIG. 6 as resting on the sheardisk or plate 20 in a manner as described with regard to FIGS. 1C and 4.The body 11 is provided with a bore 11a, but it is to be noted that thefluid escape passage means 111 shown in FIGS. 10 and 4 has beeneliminated from the modification shown in FIG. 6.

Also, the anvil A-3 is provided with a seal ring 352 which engages theinner periphery of lower body portion 11' and prevents well fluids frompassing into the bore 114: of the lower body portion 11.

Since the bore 11a is sealed off from the entry of well fluids, then thehammer H works in atmospheric pressure as it moves in the bore 11atoward the anvil A-3.

In order to provide an escape means for the fluid, or gas pressure,existing in bore 11a and in advance of the hammer H as it moves down,the top of anvil A-3 has been cut off, thereby forming a cavity 353 inthe body portion 11' which receives the atmospheric gases ahead ofhammer H as it moves down. This relieves the gas pressure ahead ofhammer H and prevents the excessive build up of pressure which mighttend to cushion the blow of the hammer H and enables substantially thefull force of the explosive E to be extended in moving anvil A3longitudinally of the body to contact the fish and obtain an impressionthereof.

PEG. 7 illustrates another modification of the invention wherein theforce of the explosive E is impinged directly on the top of anvil A3. Itwill be noted in this form of the invention that the hammer H has beeneliminated, and the explosive is similar to the explosive E shown inFIG. 1B and like parts are numbered the same as in FIG.

1B. The wadding 21 preferably rests upon the upper end 356 of the anvilA-3 as illustrated in FIG. 7. The operation of the invention with theFIG. 7 form is the same as previously described with regard to FIGS.1-6, inclusive, except that the force of the explosion gases actdirectly on the anvil rather than through the hammer H to move the anvilA4: longitudinally of the well bore. In some circumstances, it may bedesirable to use the form of the invention shown in FIG. 7 instead ofthat shown in FIGS. 1-6.

It may be desirable when employing the form shown in FIG. 7 to provideadditional weights 45 to aid in properly positioning the body B as thedevice is actuated.

The various types of anvils or jarring members at the lower end of thetool or jar of this invention are merely illustrative of the scope ofthis invention.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape, and materials as well as in the details of the illustratedconstruction, may be made within the scope of the appended claimswithout departing from the spirit of the invention.

What is claimed is:

1. An explosive jar adapted to deliver a jarring blow in a wellcomprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) a force transmitting member operably connected with said body andlongitudinally movable relative thereto when said explosive is fired,

(d) a jarring member adapted to be hit by said force transmitting memberwith a jarring force for imparting a jarring movement to said jarringmember to thereby apply a jarring force to any object contacted by saidjarring member,

(e) means for mounting said jarring member for longitudinal movementrelative to said body and so that the jarring member projects below thelower end of said body before and after detonation of the explosive, and

(f) coacting means on the body and the jarring member to prevent thejarring member from being expelled from the body.

2. An explosive jar adapted to deliver a jarring blow in a wellcomprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) means for detonating said explosive,

(d) a force transmitting member operably connected with said body andlongitudinally movable relative thereto when said explosive is fired,

(e) a jarring member adapted to be hit by said force transmitting memberwith a jarring force for imparting a jarring movement to said jarringmember to thereby apply a jarring force to any object contacted by saidjarring member, and

(f) means for mounting said jarring member for longitudinal movementrelative to said body and so that the jarring member projects below thelower end of said body before and after detonation of the explosive,

(g) means on said jarring member and said body to limit upward travel ofsaid jarring member relative to said body to maintain the jarring memberprojecting below the body at all times after a jarring blow has beenstruck, and

(h) coacting means on the body and the jarring membeer to prevent thejarring member from being expelled from the body.

3. An explosive jar adapted to deliver a jarring blow in a wellcomprising,

(a) a tubular body,

(b) a longitudinally movable hammer in said body,

(c) an explosive disposed in said tubular body above said hammer formoving said hammer longitudinally in said body,

(d) an anvil positioned in said body for longitudinal movement relativethereto,

(e) the upper end of said anvil being spaced from the lower end of saidhammer a greater distance than the travel of said anvil in said bodyafter contact by said hammer,

(f) means for guiding said hammer into contact with said anvil to imparta longitudinal jarring blow thereto which is transmitted to any objectcontacted by the lower end of said anvil,

(g) means for mounting said anvil in said body so as to dispose thelower end of the anvil below the lower end of the tubular body at alltimes, both before and after the explosive is detonated, and

(h) coacting means on the body and the jarring member to prevent thejarring member from being expelled from the body.

4. The structure set forth in claim 3 including,

(a) a relatively soft impression material at the lower end of saidanv-i-l adapted to engage a stuck object or the like in a well formaking an impression in such material of the configuration of the upperpart of the stuck object, and

(b) means mounting said material on said anvil for movement therewithwhereby the jarring force imparted to the anvil is utilized for makingthe impression in said material.

5. The structure set forth in claim 3 wherein said anvil has apuncturing head at its lower end for puncturing a bull plug or the likeor for enlarging an opening in a bull plug or the like when the jarringblow is transmitted to said anvil from said hammer.

6. An explosive jar adapted to be run in a well with a mechanical jarconnected at the upper end thereof comprising, (a) a body having achamber therein, (b) an explosive in said chamber, (c) means operable bya jarring of the mechanical jar for detonating said explosive,

(d) a force transmitting member operably connected with said body andlongitudinally movable relative thereto when said explosive is fired,(e) a jarring member adapted to be hit by said force transmitting memberwith a jarring force for imparting a jarring movement to said jarringmember to thereby apply a jarring force to any object contacted by saidjarring member; said jarring member having (1) an upper external lateralshoulder and a lower external lateral shoulder and (2) a portion withlongitudinally extending external guide surfaces; said body having (1)an internal upper shoulder adapted to be contacted by said upperexternal lateral shoulder on said jarring member when said jarringmember is in engagement with the object to be jarred, (2) a lowerinternal shoulder adapted to be engaged by said lower external lateralshoulder on said jarring member, said body having (3) sufiicient weightto prevent any appreciable upward movement thereof so that a downwardjar on the object by the jarring member is eifected.

'7. An explosive jar adapted to be run in a well comprising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(0) a firing pin adapted to detonate said explosive,

(d) a longitudinally movable firing head movable downwardly to hit saidfiring pin to effect the detonation of the explosive,

(e) a force transmitting member operably connected with said body andlongitudinally movable relative thereto when said explosive is fired,

(t) a jarring member adapted to be hit by said force transmitting memberwith a jarring force for imparting a jarring movement to said jarringmember to thereby apply a jarring force to any object contacted by saidjarring member,

(g) a wire line, and

(h) means attaching the upper end of said firing head to the lower endof said wire line to prevent relative movement therebetween for loweringthe jar in a well or the like by a lowering of said wire line.

8. An explosive jar comprising, a body having a chamber therein, anexplosive disposed in said chamber, means mounted in said body todetonate said explosive, longitudinally movable means mounted to movelongitudinally in said body and against which the explosion gases ofsaid explosives react to move same longitudinally of said body, saidlongitudinally movable means including a cavity in its lower end, leadwool in said cavity, and lead covering said lead wool whereby thejarring force imparted to said longitudinally movable means is utilizedto obtain an impression in said lead and lead wool.

9. An explosive jar adapted to be run in a well com- 7 prising,

(a) a body having a chamber therein,

(b) an explosive disposed in said chamber,

(c) a firing pin adapted to detonate said explosive,

(d) a longitudinally movable firing head movable downwardly to hit saidfiring pin to effect the detonation of the explosive,

(e) a force transmitting member operably connected with said body andlongitudinally movable relative thereto when said explosive is fired,

(f) a jarring member adapted to be hit by said force transmitting memberwith a jarring force for imparting a jarring movement to said jarringmember to thereby apply a jarring force to any object contacted by saidjarring member,

(g) a wire line,

(h) means attaching the upper end of said firing head to the lower endof said wire line to prevent relative movement therebetween for loweringthe jar in a Well or the like by a lowering of said wire line,

(i) means for mounting said jarring member for longitudinal movementrelative to said body and so that the jarring member projects below thelower end of said body before and after detonation of the explosive, and

(j) means on said jarring member and said body to limit upward travel ofsaid jarring member relative to said body to maintain the jarring memberprojecting below the body at all times after a jarring blow has beenstruck.

References Cited by the Examiner UNITED STATES PATENTS 1/40 Kinley166-63 X 12 2,628,816 2/53 Malian 175-4 X 2,729,292 1/56 Hinson 166632,978,028 4/61 Webb 16663 FOREIGN PATENTS 806,102 12/58 Great Britain.

OTHER REFERENCES 10 1946, 3rd edition, page 55?.

CHARLES E. OCONNELL, Primary Examiner.

1. AN EXPLOSIVE JAR ADAPTED TO DELIVER A JARRING BLOW IN A WELLCOMPRISING, (A) A BODY HAVING A CHAMBER THEREIN, (B) AN EXPLOSIVEDISPOSED IN SAID CHAMBER, (C) A FORCE TRANSMITTING MEMBER OPERABLYCONNECTED WITH SAID BODY AND LONGITUDINALLY MOVABLE RELATIVE THERETOWHEN SAID EXPLOSIVE IS FIRED, (D) A JARRING MEMBER ADAPTED TO BE HIT BYSAID FORCE TRANSMITTING MEMBER WITH A JARRING FORCE FOR IMPARTING AJARRING MOVEMENT TO SAID JARRING MEMBER TO THEREBY APPLY A JARRING FORCETO ANY OBJECT CONTACTED BY SAID JARRING MEMBER, (E) MEANS FOR MOUNTINGSAID JARRING MEMBER FOR LONGITUDINAL MOVEMENT RELATIVE TO SAID BODY ANDSO THAT THE JARRING MEMBER PROJECTS BELOW THE LOWER END OF SAID BODYBEFORE AND AFTER DETONATION OF THE EXPLOSIVE, AND (F) COATING MEANS ONTHE BODY AND THE JARRING MEMBER TO PREVENT THE JARRING MEMBER FROM BEINGEXPELLED FROM THE BODY.